Many smaller two-stroke and four-stroke internal combustion engines typically use an air intake boot to connect the air box to the carburetor or the throttle body if it is a fuel injected engine (collectively herein the “carburetor/throttle body”). As is shown in FIG. 1, an intake boot 01 of the prior art has a first end opening 02 with a larger cross-section that connects to the air box (not shown) and a second end opening 03 with a smaller cross-section that connects to the carburetor/throttle body (not shown). The intake boot 01 allows air to flow from the air box to the carburetor/throttle body.
The power characteristics of an engine are dependent on the velocity and volume of the air leaving the second end opening 03 of the intake boot 01 and entering the carburetor/throttle body (the “air flow”). For example, a higher velocity air flow will, in general, result in higher torque.
The problem with the intake boots of the prior art is that they do not provide a simple means for easily adjusting the velocity or volume of the air flow. It requires a given intake boot to be replaced with another intake boot with a different configuration, which different configuration causes a higher or lower velocity air flow.
It is an object of the present invention to provide a tunable air intake system in which the velocity and volume of the air flow can be easily adjusted through the use of interchangeable velocity stacks.